Coating of metal surfaces



Oct. 31, 1939. G. l. FlNcH COATING OF METAL SURFACES Filed June 22,v 1937 fare @fw M,

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Patented Oct. 31, 1939 UNITED STATES lPATENT OFFICE COATING F METAL SURFACES` George Ingle Finch, Osterley, England, assig'nor to C. C. Wakefield & Company Limited, London, England, a British company Application June 22, 1937, Serial No. 149,783

' In Great Britain June 24, 1936 Claims.

This invention relates to a process for the coating of metal surfaces.

It has been found that when metal surfaces are polished, burnished, or hammered, the normal 5 crystalline structure of the surface is destroyed andthe atoms are ydisplaced from-the positions which they normally occupy in the crystal lattice and become packed to form a-hard dense, amorphous, vitreous glass-like layer on the surface of the metal. The term hammered is used herein to include the process of rumbling, either by means of rollers or balls; either the continual contact or the impact typeof rumbling treatment is suitable to disrupt the crystal lattices Qof the vmetal of the surface being treated. It has also been found that subjecting the surface of metal to a' shearing stress in a direction along the surface is sufficient to rupture the crystal lattice and to disarrange the atoms so that they form the hard, dense, amorphous layer referred toy above. The burnished surfaces possess the peculiar property, not possessed by the normal crystalline surface of the metal, of being able to dissolve crystals of the same or of a foreign metal very readily at ordinary room temperature provided that the foreign metal is not such as to be insoluble in or incapable of alloying with the metal of the burnished surface.

According to this invention a processlfor the preparation of metal surfaces consists in coating the surface of a metal base with the same metal; or with a metal soluble in, or alloyable with, the ,metal of the base, and treating the crystalline surfaces of the base and of the coating to trans- 'vf form them into amorphous vitreous layers in the manner herein describeddiy disrupting the crystal lattices of the metal of the surface. Preferably jthe surface of the metal base is treated so as to form the aforesaid amorphous vitreous layer land i the metal .coating is subsequently applied and treated to form an amorphous vitreous layer thereon.,

A feature of the invention consists in that a number of metal coatings are successively applied, 'the surfaces of each coating being treated .in the manner above referred to.

In certain cases lit will be desirable to providel a coating lof. a metal `which is not soluble in, or

is not alloyable with, the metal of the base andv under such circumstances a further feature of the invention consists in that an intermediate coating of ja metal is applied to the base, which metal coating is solublel in, or alloyable with, both (Cl. #Z9-149.5)

In this way it will be appreciated that it is possible to apply a coating of such a metal which will be intimately bonded to the metal of the base by means of an intermediate bonding coating which coating is, at each interface, alloyed 5 with the metals on either side thereof.

A further important feature of the inventio consists in treating metal bearing surfaces in thev manner above described, applying a metal coat.- ing thereto and treating the surface of the coat- 10 ing to form the aforesaid dense amorphous vitreous layer. It will be appreciated that bearing surfaces thus treated will have a prepared surface which will not require to be run-in to provide the necessary smooth working surfaces.

A still further feature of the invention consists in providing a journal with a coating of a suitable metal,.as herein described. whereby an artificially run-in surface is formed. In one method of carrying this process into effect, a go metal bearing surface is formed by treating a ferrous metal journal, for example, by burnishing, to destroy the crystalline structure of thesurface and to transform that surface into the aforesaid amorphous vitreous layer, applying a 25 coating of a non-corrodible metal, for example, chromium or nickel, and converting the said coating into the amorphous vitreous layer referred to above. It will be appreciatedthat in this way it is possible to provide a journal with a dense, hardened surface of a non-corrodible metal of the class consisting of chromium, nickel, cobalt, beryllium, manganese and vanadium on a base of a suitable metal which, although possessing properties (e. g.'tensile strength) which render it de- 88.

sirable for use as the main part of the article, is liable to corrosion and thus, notsuited for use` in certain circumstances.

It will be appreciated that the process of this invention may be applied to the treatment of 40 bearing membersvother than journals of crank shafts and the like; for example the sleeve-valves scribed, whilst it will also be appreciated that the s cylinder bores or cylinder liners may thus also' be similarly treated.

`In the accompanying drawing, Figures 1 .to 8 are diagrammatic drawings showing the steps inA 5 the process of applying a coating to a metal base herein described.

Figure 1 shows the metal base with the normal crystalline surface.

Figure 2 shows themetal base with the amorto Figures 4 and 8.

phous vitreous surface produced by polishing, burnishing, hammering or rumbiing.

Figure 3 shows the base of Figure 2 with the 4layer of metal (which may be the same as the base-metal or different but which must be soluble in or alloyable with the metal of the base) applied to the amorphous vitreous surface.

Figure 4 is an enlarged view to show the solution or alloy of the two layers at the interface designated as mixed metal layer.

Figure 5 is the same as Figure 4 but on a reduced scale.

Figure 6 shows the metal layer with the amorphous vitreous layer formed on the surface thereof.

Figures 7 and 8 are similar to Figures 3 and 4 showing two layers of metal (which may be the same or different) on the metal base.

Figure 9 is a diagrammatic section of a shaft or rod having the metal layer or layers on the metal of the base as in Figures 4 and 8.

Figure 10 is a diagrammatic section through a tube or hollow cylinder (such as a cylinder barrel or cylinder liner) the inner surface of which 1s provided with a metal layer or layers similar The coating of metal may be deposited on the base in any suitable manner for example,y the metal coating may be formed by electro-deposition, by ashing or by dipping.

I claim:

1. A process of forming a thicl: amorphous hardened surface on a metal bearing member of ferrous metal and of the required shape and f finish which consists in forming an amorphous,

vitreous layer on the surface of the said bearing member by mechanically disrupting the crystal lattices of the surface without attritionV thereof, and without substantially altering the l configuration thereof, subsequently applying a coating of the same metal and forming an amorphous, vitreous layer of the surface of said coat- ,ing by mechanically disrupting the crystal lattices of the surface thereof without attrition also without substantially altering the configuration thereof.

2. A process of forming an articially runin" bearing member of ferrous metal which consists in forming an amorphous, vitreous layer on the surface of the said bearing member by mechanically disrupting the crystal lattices of the surface without attrition thereof, and with- .member by mechanically disrupting the crystal lattices of the surface without attrition thereof and without substantially altering the configuration thereof, subsequently applying a thin coat- -fng of a hard metal, and forming an amorphous, vitreous layer on the surface of said coat ing by mechanically disrupting the crystal lattices of the surface thereof also without attri tion thereof and without substantially altering the configuration thereof.

4. A process of preparing an artificially runin bearing member of ferrous metal which consists in forming an amorphous layer on a bearing member of the required shape and finish by disrupting the crystal lattices of the surface layers of metal without attrition thereof and without'substantially altering the configuration thereof by the application of a shear stress, applying a thin coating of a hard metal and substantially Wholly converting the said coating into amorphous metal by disrupting the crystal lattices of the metal therein without attrition thereof by the application of a shear stress to the surface of the coating also without substantially altering the configuration thereof.

5. A process of preparing an artificially runin bearing' member of ferrous metal which consists in forming an amorphous layer on a bearing member of the required shape and finish by disrupting the crystal lattices of the surface layers of metal without attrition thereof and Without substantially altering the configuration of the surface by the application of a shear stress, applying a plurality of thin coatings of hard metal and substantially wholly converting each coating into amorphous metal without attrition thereof before the application of a succeeding coating.

GEORGE JNGLE FINCH. 

